Submarine drilling and production head and method of installing same



Oct. 18, 1966 c. E. WAKEFIELD, JR 3,279,535

SUBMARINE DRILLING AND PRODUCTION HEAD AND METHOD OF INSTALLING SAME 4Sheets-Sheet 1 Filed April 3, 1961 IN V EN TOR. 6 /149455 f. WJKZVEZD,J8

47' TOP/V5 V 1966 c. E. WAKEFIELD. JR 3,279,535

SUBMARINE DRILLING AND PRODUCTION HEAD AND METHOD OF INSTALLING SAMEFiled April 5, 1961 4 Sheets-Sheet 2 I 5 I 78 54 \i F E 42 is i s I -645?; 666 i {J (2.3 y

80 f z 1 D r Ia 2b,

INVENTOR. e M6, 24. 0 /424555. WAKE/U624].

Oct. 18, 1966 c. E. WAKEFIELD, JR 3,279,536

SUBMARINE DRILLING AND PRODUCTION HEAD AND METHOD OF INSTALLING SAME 4Sheets-Sheet 5 Filed April 5, 1961 INVENTOR. 67/421555: [4444 5 /52 5454.21 i iv l 1 3 I'HJH mummy m 1966 c. E. WAKEFIELD, JR 3,279,535

SUBMARINE DRILLING AND PRODUCTION HEAD AND METHOD OF INSTALLING SAMEFlled Aprll 3, 1961 1 4 Sheets-Sheet 4 a 6 M; Q L:

INVENTOR. (A 1 7G453 5 WKE HQJQ I BY M 14 7700A/E4 United States Patent3 279 536 SUBMARINE DRILLING AND PRODUCTION HEAD AND METHOD OFINSTALLING SAME Charles E. Wakefield, Jr., Bakersfield, Califi, assignorto- The present invention is a continuation-in-part of my copendingapplication Serial No. 36,215, filed June 15, 1960, now abandoned, andrelates to the production of petroleum from a formation underlying abody of water, more particularly relating to a device for controllingflow of oil and gas from a well underlying a body of water and a methodfor landing an underwater production head at the ocean floor.

When drilling into and producing from a stratum containing oil and gasunder high pressure, a device known as a Christmas tree is normallyutilized to control flow of oil and gas from the well during the .periodof natural flow. The Christmas tree comprises an assemblage of valvesincluding generally, a master valve, one or more wing valves, and suchflow constricting and gauging devices as may be required in a particularwell. The outer casing is normally cemented into the well with thecasing spool, the tubing head, the casing head, and the variousChristmas tree components connected to the outer casing by boltingflanged fittings thereto. This, of course, requires working access tothe well head during installation.

In ofi-shore production methods heretofore known the production head hasbeen located at the surface of the water on a platform where workmen caneasily flangeup a wellhead and Christmas tree. In deeper water, however,such platforms are obviously impractical and it has been proposed tolocate the production head on the floor of the body of water. Installinga conventional Christmas tree on bottom, however, which has been done insome areas, necessarily requires costly diving operations.

It is therefore an object of my invention to provide a novel form ofproduction head for controlling the flow of oil and gas from a welldrilled in a formation underlying a body of water and also to provide amethod for installing such production head beneath the water surface.

It is also an object of my present invention to provide a submarineproduction head for installation on the ocean floor at relatively deepdepths. It is also an object of my present invention to provide asubmarine production head which can be installed remotely from afloating vessel.

It is a further object of my present invention to provide a submarineproduction head for controlling flow of oil and gas from a locationremote from the production head.

It is a further object of my present invention to provide a submarineproduction head through which drilling operations may be conducted.

Other objects and a fuller understanding of the invention may be had byreferring to the fol-lowing description and the appended claims taken inconjunction .with the accompanying drawings, in which:

FIGURE 1 is an elevation of my underwater production head showing itsposition relative to the well and submarine drilling base.

FIGURES 2a and 2b are divided longitudinal sectional views of theassembled production head showing the outer production mandrel and theinner tubing hanger mandrel assembly.

FIGURES 3 through 7 show the steps of the method for installing theproduction head in a well drilled into a formation underlying a body ofwater.

FIGURE 3 is a side elevation in diagrammatic form showing the manner inwhich the inner casing is hung preparatory to landing the assembledproduction mandrel.

FIGURE 4 is a side elevation in diagrammatic form showing the productionmandrel positioned on the surface casing landing mandrel just above thelanding base.

FIGURE 5 is a diagrammatic side elevation showing the equipment used torun the tubing into the well.

FIGURE 6 is a diagrammatic side elevation illustrating the means used toplug the production mandrel preparatory to bringing-the well in.

FIGURE 7 is a diagrammatic side elevation view showing the benthonicwell in production.

FIGURES 8a and 8b are divided longitudinal sectional views of amodification of the production head shown in FIGURES 2a and 2b employinga second string of tubing with an additional side voutlet communicatingtherewith.

With reference to the drawings, the invention is illustrated as beingembodied in an underwater production head 10 which is adapted to beoperated remotely either from a land base or a nearby off-shorestructure through control lines. The production head 10 serves thepurpose of controlling the fiow of gas and oil from the well 14 whichfunction is normally performed by a Christmas tree and well head in landbased operations. The assembled production head 10 is installed from adrilling barge 16 so that it can subsequently be remotely controlledfrom land at the completion of the drilling operation when the topopening is plugged 01f above the tubing outlet.

In another embodiment of my invention the bore of the production headassembly shown in FIGURE 2 is enlarged to permit drilling operations andthe passage of easing therethrough thus obviating the need for separateinstallation of the production head at the conclusion of the drillingoperation.

Referring now to FIGURE 1 a landing base 18 with a funnel member 20 anda sleeve 22 which guide drilling tools and various well equipmentthrough the landing base is positioned on the ocean floor at the wellopening. The lower portion 22b of the sleeve 22 is afiixed to sleeve 22in such a manner that the joint forms a seat on which the conductor pipe24 rests as shown in copending application Serial No. 19,722, of WilliamD. Leake, filed April 4, 1960. A surface pipe 26 is equipped withexternal lugs (not shown) which supports the surface pipe within theconductor pipe 24. The surface pipe 26 is provided at its upperextremity with a landing mandrel 29 onto which the blowout preventionequipment is latched during the drilling operation.

- The production head 10 includes a production mandrel 30 which isclamped together in two pieces, the lower portion 32 of which may beprovided with splines 34 and cemented into the surface pipe. T heproduction mandrel 10 functions as one piece and can be constructed asone unit, however, as a prevention measure I prefer to divide the outermandrel into two pieces as shown to facilitate removal of upper part ofthe mandrel should the need arise after the lower portion 32 has beencemented into the surface pipe. A sealing member 58 is positionedbetween the production mandrel and the lower splined portion 32. Portion32 is equipped with a bafile 36 beneath von a wire line.

cement returns. The production mandrel has a latching neck 56 near itsupper end onto which the blowout prevention equipment may be latchedwhile the tubing 54 is being run into the well.

The production mandrel 30 is provided with a casing outlet 40 and atubing outlet 42 through which latter outlet the flow of oil and gasfrom the well 14 is controlled. A casing flow line 44 is provided at theoutlet 40 and a casing valve 46 is positioned at the outlet 40 andhydraulically actuated through fluid control lines 47.

actuated control valve 50 similar to casing valve 46, and a secondspring loaded safety valve 52 held open with hydraulic pressure, whichtogether control the flow of gas and oil from the well through the flowtube 54.

The production head has an outer or production mandrel 30 and an inneror tubing hanger mandrel 31 as shown in detail in FIGURES 2a and 2b.

Water shut-01f casing 59 is threaded to the lower end of the productionmandrel 30 at 33 and the production tubing 54 is threaded into the lowerend of the tubing hanger mandrel at 68. An orientation cam 60 inside theproduction mandrel 30 is adapted to receive orientation lug 62 on thetubing hanger mandrel 31 only in such a manner that the side opening 64in the tubing hanger v mandrel 31 registers'with the tubing outlet. 42in the production mandrel 30. In FIGURE 2b, the orientation cam Y60 andthe lug 62 have been rotated 180 for the ease of illustration. As bestviewed in FIG. 8b,orientation lug 62 has an internal keyway 63 which isaligned with keyway 61 provided in the tubing hanger mandrel 31.

A key held in place by set screw 73 is fitted in the aligned keyways 63and 61 to prevent the orientation lug 62 from rotating relative to thetubing hanger mandrel 31.

The tubing hanger mandrel bore 65 is plugged above the side outlet 64with any suitable means which can be inserted remotely, such as the Otistype S packing mandrel assembly 66 which can be fitted into sealingposition The cap 67 of packer assembly 66 can be removed from a secondpacker 66b added to the packer ,assembly on an extension 69 to seal offtubing outlet 64.

Tubing 54 is threaded into a coupling member 68 which in turn isthreaded to the lower end of the tubing hanger mandrel 31. The tubingand the tubing hangermandrel are supported within the production mandrelwith a'suitable tubing hangermember such as the automatic tubing hanger70, on internal tapered portion 72 of the production mandrel. Theautomatic tubing hanger 70 hangs the tubing in the production headautomatically without the use of manually tightened ring nuts or lockingscrews. The hanger, supporting the tubing string, seats on a taperedbowl 72 in the tubing head and is locked against upward movement byspring dogs 75. As the hanger 70 enters the production mandrel 30, thespring dogs 75 surrounding the upper part of the hanger are retractedand the hanger slides-down until, as shown in FIGS. 2b and 8b,

the dogs spring automatically into the groove or shoulder 75a providedin the production mandrel. Downhole pressure from below the tubinghanger actuates or looks the automatic tubing hanger by moving thepacking unit 77 .upward which, in turn, locks the spring dogs securely 41 duction mandrel and the tubing hanger mandrel at their tubing outlets.The tubing hanger seals 71 are the primary.

seals between the tubing and the casing against upward.

flow through the casing annulus 41 above casing outlet 40. Packer cup 79also serves as a secondary seal behind primary seals 71, to restrictflow between the tubing and casing to the casing outlet 40. Packer cup79 is supported by a thimble 80 which is supported on the automatictubing hanger, 70 by a sleeve 82. Packer thimble 84 is supported inplace by the safety joint part 86 which is threaded to the tubing hangermandrel at 87.

A variation of the production head is shown assembled in FIGURES 8a and8b. In'this modification a macaroni string 122 is supported within thetubing hanger mandrel 31. A tubing hanger mandrel adaptor 124 isthreaded to the upper end of the tubing hanger mandrel 31 and has amacaroni hanger 126 threaded therein on which the inner or macaronistring of tubing 122 is hung with a coupling member 130. Packing member128 seals oflf flow between tubing 122 and the tubing hanger mandrelabove the tubing outlet 42, and sealing elements 129 serve as secondaryseals. The upper end of the macaroni hanger 126 is socketed similar tothe upper end of the head plug 88 and the safety joint 86 so that thetubing hanger mandrel or the macaroni string (122 can be removed on asocket coupling (not shown) attached to the drill string. The upper end31a of the tubing hanger V mandrel is provided with an additional outlet132 which communicates with outlet '134 in the production mandrel, thusproviding communication between the macaroni tubing 122 and the outlet120. As an example of the second recovery techniques for which thismacaroni tubing may be employed, gas may be injected into the, outlet120 and through the macaroni tubing to effect a gas lift.

Packers 136 and 138 (FIG. 8a) are provided above and below the macaronioutlet 120 to seal between the production mandrel 30 and the upperportion 127. of the tubing hanger mandrel. In FIGURE 8b the tubingoutlet 42 is shown in phantom since in this modification outlet 42 wouldnot be in the same plane with the casing outlet 40 and macaroni outlet120. i In the modification shown in FIGURES 8a and 8b the productionhead apparatus below the tubing outlet 42 would be essentially the same.asin the production head described above.

In operation the production mandrel. is first landed on the surfacecasing landing mandrel with a suitable landing sub, then the assembledtubing hanger mandrel with tubing connected thereto is lowered intoplace on the drill pipe with the socket end of a safety joint attachedto the lower end thereof, after which the plug 66 is seton a wire line.A head plug 88 is then lowered on the socketend of the safety joint (notshown) and screwed into the production mandrel. The head plug 88 isdesigned to limit upward movement of the tubing hanger mandrel in theevent of a blowout and serves as a secondary seal above packer cup 78and plug 66.

The underwater production head of the present invention is landed at the'benthos well from a drilling vessel 16 such as is disclosed in detailin copending application Serial No. 19,722, of William D. Leake, filedApril 4, 1960. With the blowout prevention equipment 92 latched to thelatching neck 28 of the surface casing landing mandrel 29 the lowersection of casing 59b is hung on a conventional casing hanger 94 whichis lowered into the surface pipe on the drill pipe 96, as shown inFIGURE 3. A suitable release tool 98 is used to release the drill pipefrom the casing hanger.

A tubing tail 99 is run through the casing hanger and the lower section59b of the casing is cemented up to the casing hanger. A flexible cementplug 100 is provided to .divide the cement from the drilling mud and adown swab 102 prevents the cement from coming back up the casing.

.A float collar 101 and -a float shoe103 are provided in theconventional manner at the lower end of the casing to prevent cementfrom coming back up the inside of the casing after displacement of thecement.

After the lower section of casing is cemented in the surface pipe thecasing is sealed olf internally with a bridge plug or a cement plug 104and the blowout prevention equipment removed from the well head, asshown in FIGURE 4. The production mandrel 30 with the upper section ofcasing 590! threaded thereon :is lowered into the surface pipe on thedrill pipe with a landing sub 110. A suitable casing splice 106 isprovided to splice the lower section 5% of the casing to the uppersection 59a of the casing. A flexible slip joint 108 may be provided 59aof the casing is cemented through a stage cement collar 112. Thus thecasing and the splined lower portion 32 of the production mandrel arecemented into the surface pipe 26 and surface casing landing mandrel 29.The baflle 36 prevents cement returns from cont-acting the clamp 38. Thesurface pipe and ,conductorpipe were previously cemented into the well.

When the production head is used as a drilling head, the casing is hungfrom the inside of the enlarged production mandrel, for example, on adonut hanger, and the surface casing is threaded to the lower end of theproduction mandrel.

The blowout prevention equipment 92 is replaced on the productionmandrel by latching the blowout prevention equipment to the latchingneck 56 of the production mandrel. The casing riser 118 which was usedin the drilling operation is then lowered and latched into the upper endof the blowout prevention equipment 92. After the casing plug 104 isdrilled out or retrieved, the tubing is hung on the tubing hangermandrel and the tubing hanger mandrel lowered into the productionmandrel, as shown in FIGURE 5. The socket end 105 of the safety joint isthreaded to the drill pipe 96 and releasably latches the safety joint 86of the tubing hanger mandrel to the drill pipe to lower the mandrelassembly into the well. The lower end of the tubing is provided with a.special packer 114 which is a means of confining zone pressure. Abovethis packer a sliding side door 116 is provided for circulating mud outof the hole after the tubing is run into the casing.

Before .the tubing hanger mandrel is lowered through the blowoutprevention equipment, plug 66 with an extension 69 and second packer 66bwhich seals the bore of the tubing hanger mandrel below the tubingoutlet, is lowered into the tubing hanger mandrel to seal off the tubingoutlet of the tubing hanger mandrel until the mandrel is lowered throughthe blowout preventers and the tubing outlet put in communication withthe tubing outlet valves 50 and 52. After the tubing hanger mandrel 31is lowered into place, however, the plug 66 is pulled up to the bargeand the second packer 66b and extension 69 are removed and a cap 67screwed into the plug 66 to seal off the tubing above the tubing outlet64 and permit tubing flow through the outlet. A head plug 88 is thenthreaded into the production mandrel 30 with the socket end 105 of thesafety joint attached to the drill pipe 96. This plug 88 serves as asecondary seal above the packer cup 78 'and also is a secondary seal tothe plug 66 as well as a safety device to prevent the tubing hangermandrel from blowing out of the hole.

At the conclusion of the drilling and cementing operations and after thewell is brought in, the drill pipe and casing riser are withdrawn to thebarge and the blowout prevention equipment retrieved. The production offluid from the well is then controlled remotely from a shore controlcenter or a control barge. Flow line 76 is connected to the fail-safevalve 52 and run on the ocean floor with the safety valve control line49 to a tank (not shown). The casing outlet hose 44 and the remainder ofthe control lines are then blanked olf and dropped on bottom. A buoymarker is attached to the blanked oif control lines and easing outlethose as shown in FIG- URE 7.

Although I have described my present invention with a certain degree ofparticularity in order to set forth the best mode of operation, it is tobe understood that my invention is not to be limited to the details setforth but should be given the full scope of the appended claims.

I claim:

1. An underwater production head for controlling the flow of oil and gasfrom a well drilled in a formation underlying a body of water,comprising in combination:

a first tubular member having a side outlet,

a second tubular member of a smaller outside diameter than the intern-a1diameter of said first tubular member,

said second tubular member having a side outlet in fluid communicationwith said outlet in said first tubular member,

said second tubular member so disposed within said first tubular memberas to form an annulus between said first and said second tubularmembers,

means for supporting said second tubular member within said firsttubular member,

means actuatable internally of said first tubular member forautomatically locking said second tubular member against verticalmovement relative to said first tubular member when said second tubularmember is supported within said first tubular member by said supportingmeans, and

means for sealing said annulus above said first and second tubularmember side outlets.

2. The apparatus of claim 1 including removable means for sealing saidsecond tubular membersinternally above said side outlet of said secondtubular member.

3. The apparatus of claim 1 including means for affixing said firsttubular member to said well.

4. The apparatus of claim 1 wherein said annulus sealing means arepressure energized.

' 5. The apparatus of claim -1 wherein said first tubular membercomprises an upper and lower section and including means for releasablyconnecting said sections, and means for securing said lower section ofsaid first tubular member into said well.

6. The apparatus of claim 1 including orientation means for registeringsaid side outlet of said second tubular mem- -ber with said side outletof said first tubular member.-

7. The apparatus of claim 1 wherein said second tubular member isconcentrically disposed within said first tubular member.

8. The apparatus of claim 1 including a third tubular member supportedwithin said second tubular member, a second side outlet in said firsttubular member and said second tubular member, said second side outletof said second tubular member being in fluid communication with saidsecond side outlet of said first tubular member, said third tubularmember having an outlet communicating with said second side outlets ofsaid first and said second tubular members. A

9. The apparatus of claim 1 including removable means for sealing thebore below said side outlet of said second tubular member to prevent theflow of oil and gas through said second tubular member side outletduring installation of said second tubular member within said first tubular member.

10. The apparatus of claim 1 including a second means for sealing saidannulus below said communicating side outlets, and

a second side outlet in said first tubular member below said secondsealing means, said second side outlet '7 communicating with saidannulus below said second sealing. means. 11. An underwater productionhead for controlling the flow of oil and gas from a well drilled information underlying a body of water comprising in combination:

a firs-t tubular member having a side outlet,

a second tubular member of a smaller outside diameter thanthe internaldiameter of said first tubular member,

said second tubular member having a side outlet in fluid communicationwith said outlet in said first tubular member,

said second tubular member being so disposed within said first tubularmember as to form an annulus between said first and said second tubularmembers,

tubing hanger means positioned on said second tubular member below saidoutlet thereof,

said tubing hanger means being arranged and constructed to support saidsecond tubular member within said first tubular member,

means actuatable internally of said first tubular member forautomatically locking said second tubular member against verticalmovement relative to said first tubular memberwhen said second tubularmember issupported within said first tubular member by saidsupportingmeans, and

means for sealing said annulus above said first and second tubularmember side outlets.

12. An underwater drilling and production head for drilling a well in aformation underlying a body of water and subsequently controlling theflow of oil and gas for said well, comprising in combination: I

a first tubular member having a side outlet, means for aflixing saidfirst tubular member to said well,

means for connecting a surface casing to said first tubular member,-

a second tubular member through which drilling tools may be operated,

said second tubular member being of a smaller outside diameter than theinternal diameter of said first tubular member and said second tubularmember having a side outlet in fluid communication with said side outletof said first tubular member,

said second tubular member being so disposed within said first tubularmemberas to form an annulus between said first and said second tubularmember, said second-tubular member having means for supporting tubingtherefrom, means for supporting said second tubular member within saidfirst tubular member, and

means actuatable internally of said first tubular member forautomatically locking said second tubular member against verticalmovement relative to said first tubular member when said second tubularmember is supported within said first tubular member by said supportingmeans.

16. An underwater production head for controlling the cfiowof oil andgas from a well drilledin a formation underlying a body of water,comprising in combination:

a first tubular member having a side outlet and a shoulder therein, asecond tubular member disposed within said first tubular member,

said second tubular member having a side outlet in fluid communicationwith said side outlet of said first tubular member,

means for supporting said second tubular member within said firsttubular member,

means actuatable internally of said first tubular member forautomatically engaging said shoulder to lock said second tubular memberagainst upward movement relative to said first tubular member when saidsecond tubular member is supported within said first tubular member bysaid supporting means, and

means for sealing between said tubular members above said side outlets.14'. An underwater production head for controlling the flow of oil andgas from a well drilled in a formation underlying a body of water,comprising in combination:

a first tubular member having a side outlet and a shoul-,

der therein,

a second tubular member of a smaller outside diameter than the internaldiameter of said first tubular member,

said second tubular member having a side outletin fluid communicationwith said side outlet of said first tubular member, 7

said second tubular member being so disposed within said first tubularmember as to form an annulus between said first tubular member and saidsecond tubular member,

means for supporting said second tubular member with in said firsttubular member,

dog means associated with said second tubular member,

means internal of said first tubular member for moving said dog meansinto engagement with said shoulder automatically when said secondtubular member is supportedwithin said'firs-t tubular member by 'saidsupporting means, to thereby lock said second tubular member againstupward movement relative to said first tubular member, and

. means for sealing said annulus above said first and said secondtubular member side outlets. 15. An underwater production head forcontrolling the a production mandrel having a side outlet,

a tubing hanger mandrel of a smaller outside diameter aha? the internaldiameter of said production man-,

said tubing hanger mandrel having a side outlet in fluid communicationwith said side outlet of said production mandrel,

said tubing hanger mandrel being so disposed within said productionmandrel as to form an annulus between said production mandrel and tubinghanger mandrel,

means for remotely lowering said tubing hanger mandrel into lockingposition with said production mandrel from said vessel,

means for supporting said tubing hanger mandrel within said productionmandrel, and

means for sealing said annulus above saidside outlets of said productionmandrel and said tubing hanger mandrel.

16. The apparatus of claim 15 including a second means for sealing saidannulus below said communicating side outlets, and

a second side outlet in said production mandrel below saidsecond sealingmeans, said second side outlet communicating with said annulus belowsaid second sealing means.

17. An underwater production head for controlling the flow of oil andgas from a well drilled in a formation underlying a body of water,comprising in combination:

9 to said shoulder as said second tubular member is lowered intooperative position in said first tubular member.

18. An underwater production head for controlling the flow of oil andgas from a well drilled in a formation underlying a body of water,comprising in combination:

a first tubular member having a side outlet,

at second tubular member of a smaller outside diameter than the internaldiameter of said first tubular memher,

said second tubular member having a side outlet in fluid communicationwith said outlet in said first tubular member, said second tubularmember so disposed within said first tubular member as to form anannulus between said first and said second tubular member,

means for supporting said second tubular member within said firsttubular member, means for locking said second tubular member in saidfirst tubular member, said locking means including means responsive topressure in said annulus below said locking means for locking saidsecond tubular member relative to said first tubular member, and

means for sealing said annulus above said first and second tubularmember side outlets.

References Cited by the Examiner UNITED STATES PATENTS 1,836,419 12/1931 Wigle 16689 X 1,923,448 '8/193-3 McCoy 166-46 2,077,480 4/ 1937Humason 166-88 2,096,565 10/ 1937 Shaffer et al 16688 2,187,839 1/ 1940Penick 166 89 X 2,469,772 5/1949 Johnson l6689 2,623,467 12/ 1952 Andrew166-95 X 2,808,229 10/ 1957 Bauer et al 175-7 2,810,442 10/ 1957 Tausch16646 X 2,859,823 ll/1958 'Bauer "166-88 2,889,886 6/1959 Gould 166-892,906,500 9/1959 Knapp et al 16666.5 X 2,918,972 12/ 1959 Tubbs 166882,970,646 2/ 1961 Knapp et al. l6666.5 X 3,032,106 5/ 1962 Focht et al.16646 3,050,120 8/1962 McSpadden 166--86 X 3,065,792 11/ 1962 Andrew 16646 3,130,785 4/ 1964 McCullough 166-46 FOREIGN PATENTS 336,323 10/ 1930Great Britain.

CHARLES E. OCONNELL, Primary Examiner. R. E. FAVREAU, AssistantExaminer.

17. AN UNDERWATER PRODUCTION HEAD FOR CONTROLLING THE FLOW OF OIL ANDGAS FROM A WELL DRILLED IN A FORMATION UNDERLYING A BODY OF WATER,COMPRISING IN COMBINATION: A FIRST TUBULAR MEMBER HAVING A SIDE OUTLETAND A SHOULDER THEREIN. A SECOND TUBULAR MEMBER DISPOSED WITHIN SAIDFIRST TUBULAR MEMBER, SAID SECOND TUBULAR MEMBER HAVING A SIDE OUTLET INFLUID COMMUNICATION WITH SAID SIDE OUTLET OF SAID FIRST TUBULAR MEMBER,MEANS FOR SUPPORTING SAID SECOND TUBULAR MEMBER AGAINST VERTICALMOVEMENT RELATIVE TO SAID TUBULAR MEMBER, SAID MEANS INCLUDING LOCKINGMEANS POSITIONED INTERNALLY OF SAID FIRST TUBULAR MEMBER ANDAUTOMATICALLY MOVABLE INTO LOCKING POSITION RELATIVE TO SAID SHOULDER ASSAID SECOND TUBULAR MEMBER IS LOWERED INTO OPERATIVE POSITION IN SAIDFIRST TUBULAR MEMBER.